1/*	$NetBSD: ieee.h,v 1.10 2007/02/02 23:07:44 christos Exp $ */
2
3/*
4 * Copyright (c) 1992, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * This software was developed by the Computer Systems Engineering group
8 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
9 * contributed to Berkeley.
10 *
11 * All advertising materials mentioning features or use of this software
12 * must display the following acknowledgement:
13 *	This product includes software developed by the University of
14 *	California, Lawrence Berkeley Laboratory.
15 *
16 * Redistribution and use in source and binary forms, with or without
17 * modification, are permitted provided that the following conditions
18 * are met:
19 * 1. Redistributions of source code must retain the above copyright
20 *    notice, this list of conditions and the following disclaimer.
21 * 2. Redistributions in binary form must reproduce the above copyright
22 *    notice, this list of conditions and the following disclaimer in the
23 *    documentation and/or other materials provided with the distribution.
24 * 3. Neither the name of the University nor the names of its contributors
25 *    may be used to endorse or promote products derived from this software
26 *    without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * SUCH DAMAGE.
39 *
40 *	@(#)ieee.h	8.1 (Berkeley) 6/11/93
41 */
42
43/*
44 * ieee.h defines the machine-dependent layout of the machine's IEEE
45 * floating point.  It does *not* define (yet?) any of the rounding
46 * mode bits, exceptions, and so forth.
47 */
48
49#include <sys/ieee754.h>
50
51#define	EXT_EXPBITS	15
52#define EXT_FRACHBITS	32
53#define	EXT_FRACLBITS	32
54#define	EXT_FRACBITS	(EXT_FRACLBITS + EXT_FRACHBITS)
55
56#define	EXT_TO_ARRAY32(u, a) do {			\
57	(a)[0] = (uint32_t)(u).extu_ext.ext_fracl;	\
58	(a)[1] = (uint32_t)(u).extu_ext.ext_frach;	\
59} while(/*CONSTCOND*/0)
60
61/*
62 * struct ieee_ext is the raw storage layout of the 80-bit
63 * extended-precision type as implemented by the FPU.  Per the
64 * respective ABI specifications, it is followed by a tail padding of
65 *
66 *   amd64: 48 bits,
67 *   i386:  16 bits.
68 */
69struct ieee_ext {
70	u_int	ext_fracl:EXT_FRACLBITS;
71	u_int	ext_frach:EXT_FRACHBITS;
72#if 0
73	u_int	ext_int:1;
74#endif
75	u_int	ext_exp:EXT_EXPBITS;
76	u_int	ext_sign:1;
77};
78
79/*
80 * Floats whose exponent is in [1..INFNAN) (of whatever type) are
81 * `normal'.  Floats whose exponent is INFNAN are either Inf or NaN.
82 * Floats whose exponent is zero are either zero (iff all fraction
83 * bits are zero) or subnormal values.
84 *
85 * A NaN is a `signalling NaN' if its QUIETNAN bit is clear in its
86 * high fraction; if the bit is set, it is a `quiet NaN'.
87 */
88#define	EXT_EXP_INFNAN	0x7fff
89#define	EXT_EXP_INF	0x7fff
90#define	EXT_EXP_NAN	0x7fff
91
92#if 0
93#define	SNG_QUIETNAN	(1 << 22)
94#define	DBL_QUIETNAN	(1 << 19)
95#define	EXT_QUIETNAN	(1 << 30)
96#endif
97
98/*
99 * Exponent biases.
100 */
101#define	EXT_EXP_BIAS	16383
102
103/*
104 * Convenience data structures.
105 */
106union ieee_ext_u {
107	long double		extu_ld;
108	struct ieee_ext		extu_ext;
109};
110
111#define extu_exp	extu_ext.ext_exp
112#define extu_sign	extu_ext.ext_sign
113#define extu_fracl	extu_ext.ext_fracl
114#define extu_frach	extu_ext.ext_frach
115
116#define LDBL_NBIT	0x80000000
117#define mask_nbit_l(u)	((u).extu_frach &= ~LDBL_NBIT)
118